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Compared with buying new at about US$250–US$289, a used TA-66 at US$200 is a fair but not standout discount. It’s close enough to the going new price that I’d call it reasonable rather than a bargain, especially since used tube gear often needs a bit of headroom for wear or replacement tubes.
The TA-66 has a solid reputation as an approachable OTL amp: it gives you that lively tube presentation, works best with higher-impedance headphones, and is a good entry into tube rolling without spending a lot. At US$200, I’d want the original box, power supply, and confirmation it’s fully quiet with no hum or channel imbalance; if those check out, it’s a sensible buy.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
xDuoo is a Shenzhen, China-based audio brand that emerged from the country’s fast-growing hi-fi manufacturing ecosystem. Its exact founding year is not consistently stated in the sources available here, and no founder is prominently verified, but the company is widely presented as Shenzhen xDuoo Technology Co., Ltd., with roots in OEM/ODM production before building its own consumer-facing identity.
The brand is best known for headphone amplifiers, DAC/amp combos, portable DACs, tube hybrids, and other desktop-and-portable electronics aimed at personal audio enthusiasts. xDuoo’s lineup has included tube headphone amps, balanced amplifier designs, digital-to-analog converters, and all-in-one sources, typically positioned for headphones rather than loudspeakers or turntables.
In the market, xDuoo sits in the value-to-mid-tier audiophile segment, with a reputation for offering ambitious feature sets, lots of connectivity, and occasional tube-flavored designs at relatively accessible prices. It is not generally considered a luxury or vintage-collector brand, but rather a practical, performance-driven Chinese hi-fi maker with a strong presence among enthusiasts seeking high features per dollar.
See all xDuoo listings on RADAR.
